Vacuum-tube structure



June 12, 1928,

f l,673,560 H. M. FREEMAN VACUUM TUBE STRUCTURE FiledA NOV. 10. 1922 Fi .2. g 1213. 3.

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. BY j' 1 v ATTORNEY- Patented June `12.', 1928.

UNITED* STATES PATENT `,oFFlcE.

HUBERT M. FREEMAN, F EAST PITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 WEST- INGHOUSE ELECTRIC 8a MANUFACTURING COMPANY, A. CORPORATION 0F PENN- SYLVANIL VACUUM-TUBE STRUCTURE.

Application led November 10, 1922. Serial No. 599,979.

posed in the evacuated portions of the tube.

and which' is characterized by its high dielectric and mechanical strength and by its low percentage of occluded gases In the usual vacuum-tube construction,

the several operating elements are supported in such manner that they are free to vibrate i0 at their upperends. When the several operating elements are set in vibration, as byv jarring, the relative motion of the elements causes variations in the operating characteristics of thetube. The result of such l5 variations is to introduce ringing sounds in such telephone devices as:V are operatively associated with the tube.

According to my invention, I provide a vacuum-tube construction wherein the sev- ;o eral operating elements are rigidly secured in position, one with respect to the other. lThe desired result may be accomplished by employing a block of insulating material which rigidly embraces the upper ends of la the operating elements. In practicing my invention, it has been found that the insulating supporting material may comprise vitritied clay.

ith these and other objects in view, my to invention further consists in the details of construction and arrangement hereinafter more fully set forth in the following description and claims and shown in the accompanying drawing, wherein: 4

Figure 1 is an enlarged front elevational view of a vacuum-tube device embodying my invention, a portion of the containing walls being broken away and the anode element and supporting block thereof being shown in section; and

Figs. Q and 3 are top and side elevational detail views oi? one form ot the block for securing the operating elements ol the tube rigidiy in predetermined spaced relation1 isA ln the embodiment of my invention shown in the drawing. an evacuated electrical device is provided in t-he form of an elongated tube 1, wherein one end is provided with a re-entrant tube 2 terminating in a supporting press 3. A tilamentary cathode element 4, which may comprise a conducting element coated with oxides of the rare-earth metals, is positioned in the axis of the tube l and has its upper and lower ends supported by carrier rods 5 and 6, respectively, which are mounted in the press 3. A spring member may be interposed between the carricr rod 5 and the upper end of the filament 4 to provide a resilient mounting for the filament. The filament carrier rods 5 and 6 may be extended through the press 3 to form external supply connections for the filament 4.

A helical grid elementB is symmetrically disposed about the cathode element 4 and may be supportedby lneans of a structure comprising a rod 9 having a portion thereof welded to the several helices of the grid 8 and having arms which are welded to a main carrier rod 11, the latter being supported in the press 3. The nain carrier rod 1l may be extended through the press 3 to provide an external terminal connection for the helical grid element 8.

A cylindrical anode 12 is co-axially positioned with respect to the. grid and lament elements and is supported by means of a pair of, carrier rods 13 and 14 extending from the press 3. One carrier rod, say 13, may be extended through the press 3 tov provide an external terminal connection.

As may readily be seen, in such construction as that just described, the several elements of the vacuum-tube structure are free to vibrate. Hence, when the -vacuum-tube structure is jarred and the relative spacing of the several elements is varied in accordance with the vibration thereof, microphonic noises are introduced in the operation of the tube. ln the course of much experimental' work it was found that the microphonic noises were avoided by rigidly securing together tlie'several tube elements to prevent variations in the relative spacing of Vthe same.

Une method for accomplishing the abovementioned desired result consist in providing' a block 15 oi insulating material nav-` lili@ ing a plurality of perforations 16, 17 and 18 corresponding in diameter and in position to the main grid carrier rod 11, the

anode 12 and the upper filament carrier rod 5, all'as shown in the drawing. The block 15 ma com rise a composition of clay and a vitri ying Eux or it may comprise a virtrilied clay, that is, orcelain.

The block 15 is prefera ly positioned immediately adjacent to the upper ends of the several elements just mentioned, with the top portions of the anode 12 and of the carrier rods 5 and 11 extending through the respective perforations. The block 15 may be rigidly secured to the several tube elements by cementing the same with any well-known form of cement, as, for example, a mixture of sodium silicate and flint.

IVhen the vacuum-tube structure of Fig. 1 is jarred, the insulating supporting block 15 prevents the several elements from vibrating independently to varyvthe relative spacings thereof.

IVhile I have described a specific embodiment of my invention involving a specific application thereof, for the purpose of describing the same and illustrating the various principles and applications thereof. it is apparent that various changes and modifications may be made therein Without dcparting from the spirit of my invention. I desire, therefore, that only such limitations shall be imposed thereon as are indicated in the appended claims or demanded by the prior art.

I claim as my invention:

1. In a vacuum tube, a plurality of concent-ric electrodes one of which is a cylinder, a plurality of parallel standards supporting the other electrodes and an insulating block embracing said cylinder and having perforations through which said standards ass. f p 2. In a vacuum tube, a plurality of concentric electrodes, standards for supporting said elemrodes having parallel portions outside the outer one of said electrodes and an insulating block having a large perforation into which the upper end of said outer electrode fits.

3. In a vacuum tube, a cylindrical plate, a grid within said plate, a standard exterior to said plate, a body of insulation material secured near one end of said late and havingr a perforation through which said standard passes, and a supporting structure extending from said grid to said standard and secured thereto on opposite sides of said hoy.

4. In a vacuum tube. concentric electrodes,

a dat body of insulating material fitted to and surrounding the exterior electrode` said body having perforations at each side of said exterior electrode. standards extending through said perforat-ions and means secured to said standards on one side of said body and extending from said standards toward each other for supporting the inner electrodes.

In testimony whereof. I have hereunto subscribed my name this 27th day of October HUBERT M. FREEMAN. 

